Square steel pipes and round pipes have different properties and are used for different purposes. Square pipes have a larger surface area than round pipes, which makes them more suitable for applications where strength and durability are required. They are also easier to weld and cut, making them ideal for construction and manufacturing applications. On the other hand, round pipes are better suited for applications where fluid or gas flow is required, such as in plumbing or HVAC systems. Ultimately, the choice between square and round pipes depends on the specific application and the desired properties. 

Square steel pipes are preferred over round pipes in situations where:1. Aesthetic appeal: Square steel pipes are preferred in situations where the aesthetic appeal of the structure is important. Square pipes give a modern and sleek look to the structure.2. Structural stability: Square steel pipes are preferred in situations where structural stability is important. The square shape provides more surface area for the connection points, which makes it stronger and more stable.3. Space utilization: Square steel pipes are preferred in situations where space utilization is important. The square shape allows for better utilization of space, as it can fit into corners and tight spaces more easily than round pipes.4. Welding: Square steel pipes are preferred in situations where welding is required. The flat sides of the square pipes make it easier to weld and provide a better surface for welding.5. Fabrication: Square steel pipes are preferred in situations where fabrication is required. The square shape allows for easier cutting and shaping, making it easier to fabricate into different shapes and sizes.